Electrical tapes, as well as tapes and adhesive sheets for other applications which require stretching, typically use a polyvinylchloride (vinyl) substrate or backing, upon which the adhesive is coated. This material provides excellent mechanical properties such as elongation. Such vinyl materials are highly plasticized, with some containing up to 60 percent by weight (wt-%) plasticizers. Vinyl electrical tapes and sheets have traditionally been made by first applying a primer layer to a vinyl backing prior to the application of the adhesive. This primer provides the required anchorage of these two (in principle) incompatible layers. New and improved primers that provide better adhesion between the vinyl backing and the adhesive are needed.